I have no idea how good a Valkyrie is, but I made Miriel into one.  35+7 mg.   She's an insanely powerful magician.

Here's the units I think I'll stick with for the duration of the game:

• Chrom (Great Lord)
• Lissa (War Cleric)
• Virion (Sniper)
• Smeags (Grandmaster... although once I get Galeforce I'm switching to Assassin)
• Gaius (Trickster)
• Ricken (Sage)
• Lucina (Great Lord)
• Tharja (Sorcerer)
• Sumia (Dark Flier)
• Morgan (Grandmaster)
• Nowi (Manakete)
• Panne (Taguel)
• Cherche (Wyvern Lord)
• Stahl (Paladin)
• Sully (Great Knight)
• Lon-qu (Swordmaster)

Here's teh units you should stick with for the rest of the game:

Chrom

Smeags

Armsthrift + 33 luck.

Y'know that awesome weapon that breaks after only a few uses? Yeah, merc-Donnel gets to use it three times as long as your swordmaster does.

Currently working on a eugenics program involving Donnel. Y'see the only people who have growths that can compete with him are the manaketes. Both their personal growth rates and the manakete class growth rates are well above average. Donnel himself can only keep up because of that crazy skill.

So... Donnel + Nowi = Nah with Aptitude.

Avatar + Nah = Morgan as a manakete with Aptitude.

My unstoppable draconic master race shall usher in a bold new era of capped stats!

Nah doesn't really need Aptitude though. She hits her caps fairly early, especially on Speed (which has a disgustingly low cap, to be honest: it's her only real weakness). You'd be better served passing down a more powerful skill like Astra or Lifetaker, or even Renewal.

You're probably right and I'm being a little silly, but I see mechanics like these and I've gotta try pulling crazy crap with them. Don't you think Morgan with Ignis and capped str and mag has potential?

Not planning on keeping these guys long as dragons, anyway, since the skills are so weaksuace. Was planning on second sealing most of the children right away, actually.

It does seem like some of the children will be worth taking the time to cultivate. Morgan and Lucina seem like they'll do well for themselves. Less so with Laurent (although the parentage was part problem. All he got from Stahl was Outdoor Fighter).

My Save Files as Follows (All three started Hard/Classic, Save 1/Save 2 I beat and are now on Lunatic with the same teams):

Save 1

• Chrom (Great Lord) x Olivia (Dancer)
• Avatar(Mage-ish Grandmaster) x Tharja (Sorcerer)
• Lissa (Valkyrie) x Libra (War Cleric)
• Gaius (Assassin) x Sumia (Falcon Knight)
• Sully (Paladin) x Vaike (Warrior)
• Indigo (Hero) x Kjelle (Great Knight)
• Noire (Sniper) x Owain (Swordmaster)

Save 2

• Chrom (Great Lord) x Avatar (Swordmaster)
• Kellam (General) x Olivia (Dancer)
• Gregor (Hero) x Nowi (Manakete)
• Lissa (Valkyrie) x Ricken (Sage)
• Cherche (Dragonmaster) x Vaike (Berserker)
• Lucina (Great Lord) x Gerome (Dragonmaster)
• Nah (Manakete) x Owain (Paladin)

Save 3

• Chrom (Great Lord) x Sully (Griffon Rider)
• Avatar (Sword/Magic Grandmaster*) x Anna (Trickster)
• Maribelle (Valkyrie) x Henry (Sorcerer)
• Lon'qu (Swordmaster) x Olivia (Dancer)
• Stahl (Great Knight) x Cordelia (Falcon Knight)
• Indigo (Hero) x Severa (Hero)
• Morgan (Mage-ish Grandmaster) x Brady (Dark Knight)

*Will be a Demonfighter once the proper DLC comes out

O and I beat chapter 6 and 7 on Lunatic! 

Kids get the last-equipped skill of each parent at the time you do the mission to recruit them. So kids can start off at level 10 with a bonus pair of level 35 skills. All you have to do is pick each parent's awesomest skill, unequip an re-equip it, then do the paralogue for the brat. If the parent has no awesome skills, I suggest waiting until they do before hitting the mission. 

One exception I've found is the all-stats +2 skill, so I'm guessing kids can't inherit DLC skills. I've read they can get gender-specific ones from the opposite gender, though. 

Yeah does seem that way, though then again, those two are sorta woven into the story so need to be good from the get-go. The others, less so.